1. Field of the Disclosure
The present disclosure relates to a production of 1,1,1,4,4,4-hexafluoro-2-butene by using 2,2-dichloro-1,1,1-trifluoroethane and copper.
2. Description of Related Art
The fluorocarbon industry has been working for the past few decades to find replacement refrigerants and foam expansion agents for the ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) being phased out as a result of the Montreal Protocol. The solution for many applications has been the commercialization of hydrofluorocarbon (HFC) compounds for use as foam expansion agents, refrigerants, solvents, fire extinguishing agents and propellants. These new compounds, such as HFC-245fa (1,1,1,3,3-pentafluoropropane), have zero ozone depletion potential and thus are not affected by the current regulatory phase-out as a result of the Montreal Protocol.
The HFCs do not contribute to the destruction of stratospheric ozone, but are of concern due to their contribution to the “greenhouse effect”, i.e., they contribute to global warming. As a result of their contribution to global warming, the HFCs have come under scrutiny, and their widespread use may also be limited in the future. Thus, there is a need for compositions that meet both low ozone depletion standards as well as having low global warming potentials. Certain hydrofluoroolefins, such as 1,1,1,4,4,4-hexafluoro-2-butene (F11E), are believed to meet both goals.
In U.S. Pat. No. 5,516,951, Aoyama disclosed a process for making F11E by reacting 2,2-dichloro-1,1,1-trifluoroethane (HCFC-123) with copper and an amine. However, the yield is low. According to the results reported by Xu, et al. in J. Org. Chem. 1997, 62, 1576-1577, such processes generate CF3CH2Cl byproduct which is hard to separate and other impurities.